Wired in resistors, now injectors wont fire.

[carbonkid]

I searched and have found nothing on this is the sr forum. Im running Msd 72lb low imp injectors. Ok here it goes, i got the resistors and msd clips from jgy. I solder them in correctly, resistor in the thiner wire(colored wires, not the red) in every injector just like Jgy told me to. I also wired in my n62 maf, following the diagram i found on nico. Car cranks over and wont start, took the injectors out to see if they are fireing and they are not. Called Jgy they told me they only heard of that happening one other time, they were running msd injectors on a power fc and they wouldnt fire, same like me. They told me to call apexi, maybe they would know. But they never heard of that happening, and there were no special settings on the fc to "fix" it. So i called msd, they told me how to check to see if the injectors work and they did.

So im at this point. Injectors work, there low imp so i need resistors, i got fuel coming into the rail, fuel pump is turning on, i went over the harness like 10 times to see if i left something unpluged or wired something incorrectly but no. Anyone ever have a problem like this? I about to try a stock computer out.

[Emperor_Tha]

U try using a noid tester on the injector connector.

[rustest86]

grab a 12v test light and probe each wire to the injector, the resistor should be on the ecu/ground side. not the 12v side. if there installed on the 12 volt side they wont open. power fc or any other ecu/management shouldnt do that unless its installed wrong.

[the converted]

It shouldn't matter what side the resistors are wired in on. Did you possibly reverse the polarity? That's about the only reason I could see them not working. You could try switching one and see if that changes anything.

[rustest86]

if the resistors are wired in on the 12v side it will drop the voltage going to them and they wont open. all injectors regardless on of being low or high resistance need 12v to open. the resistors are needed because ecu doesnt have built in resistors, and is desighned for high resistance injectors. also resistors cant be wired backwards, only diodes.

[the converted]

The resistors in this case are installed as current limiting devices, not voltage, and won't make a difference. ECUs that are designed for low impedance use pwm to control the current through the injector.

[rustest86]

yes they are current limiting devices. because they need to limit the current going to the ecu not the injector. if you look at any factory installed resistors, ie on mitsubishi, honda, mazda, and toyota to name a few, the resistors are istalled on the ecu side to limit current flow to the ecu. all injectors require 12v to operate. if you place the resistor on the 12v side it will lower the voltage going to the injector, to say 7-9 volts "im throwing out a # on that" because it depends on the accuall resistance of the resistor.

[the converted]

A resistor would do the same thing independent of where it is in the circuit. It's also funny you mention Honda because I know for a fact that theirs are on the positive side from doing mpfi conversions in ef chassis.

I do think that we are arguing semantics at this point anyway and that this probably isn't the issue that the OP is having anyway.